To be able to add a "Share this video to Instagram" feature to your software, you need to integrate with the Facebook Graph API and request certain permissions which will have you need to go through their App Review process, which means a human will need to take a look at it and decide whether you are a doing things to their liking.
The specific permissions are:
The special thing about giving a reviewer something to test here is the requirements on top of that. You need a Facebook user that manages a page, and that page needs to be connected/linked to an Instagram Business account (not a normal or Creator account, at least at the time of writing).
Usually the reviewer gets login credentials for your own system and then additionally a so called test-user that you can prepare in the App Dashboard on developer.facebook.com. However, you can't fully prepare this for them. Test-users cannot be connected to an actual Instagram account, you'll just see a generic error message as you try. There's also no such thing as Instagram Test Users anymore (I have found an outdated guide showing UI options for this, so it has existed at some point in the past).
You are also going to find many unanswered or unsolved forum posts about how to actually properly prepare the test setup for this kind of review, with no actual definite solution anywhere. Which is why many people fail the review, and it's a very time consuming and frustrating process overall. The closest thing to a solution that I found was this post: https://developers.facebook.com/community/threads/1311403425685469/
They recommend to clearly tell the reviewer what kind of requirements they need. This has actually worked for me, so I will forward the same recommendation. I did not prepare a Facebook test-user, nor anything on the Instagram side of things. I only prepared login credentials for our own software and a list of steps how to test the integration feature. At the top of my submission I tried to describe the FB-Insta connection that was needed:
As far as I can tell by my research, I can not provide a Facebook test-user to you for this review, as test-users cannot be connected to Instagram, the API does not allow it.
So please prepare this beforehand, as I am unable to prepare it for you:
- You need a Facebook user who owns/is admin of a managed page
- You need an Instagram Business account that is connected to that managed page
With that setup, please log into our app using the "Test Credentials" below.
... Test Credentials ...
... List of steps on how to test ...
This is what got us approved in the end (accompanied with a full screencast of me from login, over giving FB/Insta permissions, to showcasing the feature). I may just have gotten lucky, maybe the fact we finished access verification in between reviews helped, I don't know. Took me four attempts to get that review approved, which was frustrating enough to write this down and hope I can spare someone else the pain. Cheers